The following definitions are employed throughout the detail discussion:
activating stationxe2x80x94the DTE, DCE and other associated terminal equipment which originates an activation of an xDSL service;
answering stationxe2x80x94the DTE, DCE and other associated terminal equipment which answers a call placed on the PSTN (GSTN);
carrier setxe2x80x94a set of one or more frequencies associated with a PSD mask of a particular xDSL Recommendation;
CAT3xe2x80x94cabling and cabling components designed and tested to transmit cleanly to 16 MHz of communications. Used for voice and data/LAN traffic to 10 megabits per second;
CAT5xe2x80x94cabling and cabling components designed and tested to transmit cleanly to 100 MHz of communications;
communication methodxe2x80x94form of communication sometimes referred to as modems, modulations, line codes, etc.;
downstreamxe2x80x94direction of transmission from the xTU-C to the xTU-R;
Galfxe2x80x94an octet having the value 8116; i.e., the ones complement of an HDLC flag;
initiating signalxe2x80x94signal which initiates a startup procedure;
initiating stationxe2x80x94DTE, DCE and other associated terminal equipment which initiates a startup procedure;
invalid framexe2x80x94frame that has fewer than four octets between flags, excluding transparency octets;
messagexe2x80x94framed information conveyed via modulated transmission;
metallic local loopxe2x80x94communication channel 5, the metallic wires that form the local loop to the customer premise;
responding signalxe2x80x94signal sent in response to an initiating signal;
responding stationxe2x80x94station that responds to initiation of a communication transaction from the remote station;
sessionxe2x80x94active communications connection, measured from beginning to end, between computers or applications over a network;
signalxe2x80x94information conveyed via tone based transmission;
signaling familyxe2x80x94group of carrier sets which are integral multiples of a given carrier spacing frequency;
splitterxe2x80x94combination of a high pass filter and a low pass filter designed to split a metallic local loop into two bands of operation;
telephony modexe2x80x94operational mode in which voice or other audio (rather than modulated information-bearing messages) is selected as the method of communication;
transactionxe2x80x94sequence of messages, ending with either a positive acknowledgment [ACK(1)], a negative acknowledgment (NAK), or a time-out;
terminalxe2x80x94station; and
upstream: The direction of transmission from the xTU-R to the xTU-C.
The following abbreviations are used throughout the detailed discussion:
ACKxe2x80x94Acknowledge Message;
ADSLxe2x80x94Asymmetric Digital Subscriber Line;
CCITTxe2x80x94International Telegraph and Telephone Consultative Committee;
CDSLxe2x80x94Consumer Digital Subscriber Line;
DSLxe2x80x94Digital Subscriber Line;
FSKxe2x80x94Frequency Shift Keying;
GSTNxe2x80x94General Switched Telephone Network (same as PSTN);
UDSLxe2x80x94High bit rate Digital Subscriber Line;
HSTU-Cxe2x80x94handshaking portion of the xDSL central terminal unit (xTU-C);
HSTU-Rxe2x80x94handshaking portion of the xDSL remote terminal unit (xTU-R).
ISOxe2x80x94International Organization for Standardization;
ITU-Txe2x80x94International Telecommunication Unionxe2x80x94Telecommunication Standardization Sector;
NAKxe2x80x94Negative Acknowledge Message;
NTUxe2x80x94Network Termination Unit (Customer premise end);
PBOxe2x80x94Power Back Off;
PMExe2x80x94Power Management Exchange
PMMxe2x80x94Power Measurement Modulation;
PMMSxe2x80x94Power Measurement Modulation Session;
POTSxe2x80x94Plain Old Telephone Service
PSDxe2x80x94Power Spectral Density;
PSTNxe2x80x94Public Switched Telephone Network;
RADSLxe2x80x94Rate Adaptive DSL;
VDSLxe2x80x94Very high speed Digital Subscriber Line;
xDSLxe2x80x94any of the various types of Digital Subscriber Lines (DSL);
xTU-Cxe2x80x94central terminal unit of an xDSL; and
xTU-Rxe2x80x94remote terminal unit of an xDSL.
1. Field of the Invention
The present invention is directed to a high speed communications device, such as, for example, but not limited to, a modem, a cable modem, a xDSL modem, a satellite communication system, a point-to-point wired or wireless communication system, which includes a handshaking or initializing protocol, and in particular, to an apparatus and method that provides means to robustly select measurement procedures and robustly report the results of such measurement procedures.
2. Discussion of Background and other Information
One of the important functionalities of the various xDSL schemes is to accurately control the amount of transmit power used on a specific xDSL line. Since each local loop used for xDSL has unique parameters, such as, for example, attenuation, interference, crosstalk, etc, it is desirable to accurately measure those parameters before blindly transmitting large amounts of power into the loop. Heretofore, each xDSL scheme has used it""s own proprietary style of power measurement and control, with varying degrees of measurement and control.
Additionally, the power control measurement procedures of the prior art were typically used after the xDSL modulation had started, with large amounts of power already being trasmitted.
Accordingly, there is a need for an apparatus and method that provides means to robustly select measurement procedures and robustly report the results of such measurement procedures, so as to minimize the amount of transmission power used to transmit data.
The ITU-T has published recommended methods for initiating data communication over voice band channels. The following three Recommendations have been produced, the subject matter of which is expressly incorporated herein by reference in their entirety:
1) Recommendation V.8, entitled xe2x80x9cProcedures For Starting Sessions Of Data Transmission Over The General Switched Telephone Networkxe2x80x9d, published in September, 1994;
2) Recommendation V.8bis, entitled xe2x80x9cProcedures For The Identification And Selection Of Common Modes Of Operation Between Data Circuit-Terminating Equipments (DCEs) And Between Data Terminal Equipments (DTES) Over The General Switched Telephone Networkxe2x80x9d, published in August, 1996; and
3) Recommendation G.994.1, entitled xe2x80x9cHandshake Procedures For Digital Subscriber Line (DSL) Transceiversxe2x80x9d, published in June 1999.
It is noted that document (3) is the final version of Temporary Document MA-006 that was published in March, 1999.
Accordingly, an object of the present invention is to provide a uniform power measurement procedure that can be used for all xDSL schemes. Another object of the instant invention is to perform the uniform power measurement procedure prior to the selection of the specific xDSL scheme. The procedure of the instant invention may be implemented as an extension to an xDSL handshaking and selection procedure, such as, but not limited to, that shown in commonly assigned U.S. patent application Ser. Nos. 09/217,556 filed on Dec. 21, 1998 and/or 09/281,813 filed on Mar. 31, 1999, and/or ITU-T Recommendation G.994.1, published in June, 1999. Integrating the power control and measurement procedure with the xDSL selection procedure allows a more accurate selection of the particular xDSL modulation scheme, based on the power measurement results. The present invention also allows for a more accurate determination of the minimum needed frequency dependent transmission power during a data transmission mode.
According to an object of the present invention, an apparatus is disclosed for determining transmission parameters while initializing a communication link. A parameter indicating device, that is associated with an initiating communication device, transmits first transmission parameters that can be used by the responding communication device to a responding communication device. In response to the transmitted first transmission parameters, a measurement receiving section, that is associated with the initiating communication device, receives first signals issued by the responding communication device.
According to an advantage of the invention, the initiating communication device also includes a parameter receiving device that receives, from the responding communication device, second transmission parameters that can be used by the initiating communication device, and a measurement transmission section that transmits second signals to the responding communication device, in response to the received second transmission parameters.
According to a feature of the invention, the responding communication device additionally includes a parameter indicating device that transmits second transmission parameters to be used by the initiating communication device to said initiating communication device. It is noted that the first transmission parameters are related to at least one of a power level, a frequency bandwidth, a duration, and a carrier density of the communication link.
According to another feature of the invention, the responding communicating device also includes a measurement receiving section that receives transmitted signals, so that the initiating communication device and the responding communication device can perform an exchange of information between respective measurement receiving sections.
According to another object of the invention, an apparatus is disclosed for determining transmission parameters while initializing a communication link. A parameter receiving device that is associated with an initiating communication device receives transmission parameters that can be used by the initiating communication device. A measurement transmission section that is associated with the initiating communication device transmits signals to the responding communication device, in response to the received transmission parameters.
According to an advantage of the invention, the responding communication device also includes a parameter indicating device that transmits, to the initiating communication device, the transmission parameters that can be used by the initiating communication device. The transmission parameters are related to at least one of a power level, a frequency bandwidth, a duration, and a carrier density of the communication link.
According to a further advantage of the invention, the responding communicating device also includes a measurement receiving section that receives the transmitted signals, the initiating communication device and the responding communicating device performing an exchange of information between respective measurement receiving sections.
Another object of the present invention is the disclosure of an apparatus for establishing a communication link using a determined amount of transmission power. A parameter indicating device that is associated with an initiating communication device transmits, to a responding communication device, first transmission parameters that can be used by the responding communication device. A measurement receiving section that is associated with the initiating communication device, receives first signals issued by the responding communication device in response to the first transmission parameters. Then, a selecting device that is associated with the initiating communication device transmits, to the responding communication device, power level parameters that can be used by the responding communication device.
An advantage of the invention is that a parameter receiving device that is associated with the initiating communication device receives, from the responding communication device, second transmission parameters that can be used by the initiating communication device. A measurement transmission section that is associated with the initiating communication device transmits second signals to the responding communication device, and a selecting device, associated with the responding communication device, transmits, to the initiating communication device, power level parameters that can be used by the initiating communication device.
Another advantage of the invention is the inclusion of a configuring device that is associated with the initiating communication device. The configuring device sets power level transmission characteristics to be used by the initiating communication device in response to the transmitted power level parameters.
A still further advantage of the invention is that the initiating communication device and the responding communication device perform a communication link startup procedure after the power level parameter is selected.
Another object of the present invention relates to an apparatus for establishing a communication link using a determined amount of transmission power. A parameter receiving device, associated with an initiating communication device, receives, from a responding communication device, transmission parameters that can be used by the initiating communication device. A measurement transmission section, associated with an initiating communication device, transmits signals to a measurement receiving section of a responding communication device, in response to the transmission parameters. A selecting device, associated with the responding communication device, transmits, to the initiating communication device, power level parameters that can be used by the initiating communication device.
A configuring device that is associated with the initiating communication device may additionally be provided to set power level transmission characteristics to be employed.
A feature of the invention is that the initiating communicating device and the responding communicating device perform a communication link startup procedure after the power level parameter is selected.
A still further object of the invention concerns a method for determining an amount of transmission power to use while establishing a communication link. An initiating communication device transmits a power measurement signal to a responding communication device. The responding communication device acknowledges reception of the power measurement signal, and additionally transmits to the initiating communication device, received power measurement values. The responding communication device the indicates transmission characteristics of the initiating communication device to the initiating communication device. The initiating communication device then utilizes the transmission characteristics received from the responding device during a subsequent transmission.
The responding communication device may additionally transmit a signal to the initiating communication device proposing transmission characteristics of the power measurement signal to be received by the responding communication device. A communication link startup procedure may also be initiated after the transmission characteristics has been indicated.
According to a feature of the invention, at least one of an initiation, a parameter, a result, and an acknowledgment is transmitted by digital messages. Additionally, at least a portion of the digital messages may be transmitted at substantially a same time as the power measurement signal.
According to another object of the invention, a method is disclosed for determining frequency dependent amounts of transmission power to use while establishing a communication link. According to the method, an initiating communication device transmits a power measurement signal with characteristics that are frequency dependent to a responding communication device. The responding communication device indicates the frequency dependent transmission characteristics of the initiating communication device to the initiating communication device. The initiating communication device then utilizes the frequency dependent transmission characteristics received from the responding communication device during a subsequent transmission.
According to a feature of the invention, the responding communication device transmits frequency dependent received power measurement values to the initiating communication device. According to another feature of the invention, the responding communication device transmits a signal that proposes the frequency dependent transmission characteristics of the power measurement signal to be received by the responding communication device, to the initiating communication device.
A further object of the invention pertains to a method for determining an amount of transmission power to use while establishing a communication link. A power measurement signal is transmitted from an initiating communication device to a responding communication device, in which the power measurement signal is transmitted at a predetermined power level. The power measurement signal is re-transmitted at incrementally higher power levels (such as, for example, 2 db increments), which may be at predetermined time intervals such as, for example, 200 ms), until the responding communication device issues a signal representing that the power measurement signal was adequately received. A transmit power level is then set for establishing a communication link between the initiating communication link and the responding communication device in response to the signal representing that the power measurement signal was adequately received.
According to a feature of the invention, a communication link startup procedure may be initiated after the transmit power level parameter has been set. It is noted that the transmitted power measurement signal may be encoded as digital messages on a negotiation and control channel that is exchanged between the initiating communication device and the receiving communication device.
An additional object of the invention concerns an apparatus for measuring frequency dependent power during handshaking of a communication link. An indicating device that is associated with an initiating communication device transmits frequency band transmission parameters (that can be used by the responding communication device), to a responding communication device. A measurement transmission section that is associated with an initiating communication device transmits (to a measurement transmission section of a responding communication device) first signals in such a maimer that a power level varies by frequency bands. A measurement receiving section of the initiating communication device receives second signals, in which the power level varies by frequency bands issued by a measurement transmission section of the responding communication device, with the second signals being received in response to the transmitted first signals.
According to a feature of the invention, the first signals may be shaped by a frequency band transmission device that functions to shape the first signals by at least one of a flat filter, a sloped filter, and a b-spline filter.
Another feature of the invention is that the transmitted first signals may be subjected to parameterized templates, so as to allow a non-linear gain.
Another method is disclosed for establishing communication transmission parameters during a communication link initialization, by transmitting, by an initiating communication device (such as, for example, an xTU-R), a first digital message having parameters for a downstream power measurement sequence; transmitting, by a responding communication device (such as, for example, an xTU-C), a second digital message having parameters for an upstream power measurement sequence, and also including substantially the same said parameters of said first digital message as parameters of said second digital message; transmitting, by the initiating communication device, a third digital message that acknowledges the parameters and a mode selected by the responding communication device; transmitting, by the initiating communication device, a power measurement signal that employs the parameters; transmitting, by the responding communication device, the power measurement signal that employs the parameters; transmitting, by the initiating communication device, a fourth digital message containing a result of the power measurement signal transmitted by the responding communication device and a desired power reduction level; transmitting, by the responding communication device, a fifth digital message containing a result of the power measurement signal transmitted by the initiating communication device and the desired power reduction level; exchanging a final operating characteristic between the initiating communication device and the responding communication device to select and/or acknowledge a mode by the initiating communication device and the responding communication device; and, starting a training session of the initiating communication device and the responding communication device.